Picture hook



FIG. 1 is a left side, top and front perspective view of a picture hook showing my new design;

FIG. 2 is a front elevation thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a rear elevation thereof; and

FIG. 6 is a right side elevation thereof, the left side elevation view being a mirror image. 

The ornamental design for a picture hook, substantially as shown and described. 